In livestock facilities such as pig firming and diary firming, excreta are discharged every day and an amount of excreta is generally proportional to a breeding number of animals. Usually, the excreta is composted by means of microorganisms
Disposal of excreta by microorganisms, however, consume too long time because of higher percentage of liquid components in the excreta. In some areas, the livestock excreta generated in large quantities are left on ground without treatment, resulting in contamination of ground water, which has become a cause of social problems.
Therefore, how to dispose of excreta is a problem to be solved today. In particular, it is not allowed any more to damp unsanitary excreta which give off a bad smell due to the recent severe regulation for environmental protection.
An amount of excreta of livestock is increasing along with expansion of the livestock scale but it is not easy to dispose of excreta generated daily in a large quantity efficiently in a short period of time. Therefore, disposal of livestock excreta is a heavy burden for livestock farmers.
Under such situation, it was proposed to use an insect bio-processing system for processing animal excreta so as to reduce the above burden (see Patent Document 1).
The insects bio-processing system disclosed in Patent Document 1 comprises a means for conveying sequentially processing-containers on which animal excreta are placed, a means for preying animal excreta onto an empty processing-container conveyed successively, a means to depositing eggs or larvae of housefly into unfermented excreta in the processing containers, a means for maturing excreta for a require duration in the processing containers stacked in multiple stages, a means to collect larvae or pupa metamorphosed from the larvae of housefly crawling out of the processing-containers, and a means for recovering finished or matured excreta from the processing-container which is advanced successively.
In this insect bio-processing system, reduction of harm or detoxification of excreta can be realized by preying or feeding animal excreta to housefly.